X-ray apparatus



ug- 18, 1935-' A. KUNTKE Er Al. y2,051,411

, x-RAYl APPARATUS Filed Feb. 10, 1932 ggd.

Patented Aug. 18, 1936 x-RAY APPARATUS Alfred Kuntke and Willem HondiusBoldingh, Eindhoven, Netherlands, assignors to N. V. PhilipsGloeilampenfabrieken, Eindhoven,

Netherlands Application February 10, 1932, Serial No. 592,120 In theNetherlands February 14, 1931 12 Claims. (Cl. Z50-34) Our inventionrelates to an X-ray installation for taking both radioscopies andradiographs, and is particularly important in connection with makinginstantaneous exposures.

Prior installations for this purpose comprise, as a rule, a device forsupplying different energies to the X-ray tube in order that the tubemay operate during the exposure with a higher energy radiation than isrequired for uoroscopy. Generally, the X-ray tube is movable to enablean accurate adjustment of the source of rays relative to the object tobe irradiated.

Our invention relates to an installation which takes advantage of thefact that the conditions for iiuoroscopic examination are in manyrespects opposite to those for taking an exposure. For

. taking radiographs it is not only desirable that a higher energyradiation be used, but also that, to obtain a photograph of sharpdefinition, the tube be at a greater distance from the ray-sensitivelayer and the object than is required in fluoroscopy. The main purposeof iluoroscopic examination is, in most cases, to select those parts ofthe object to be radiographed, and the definition of the image is ofminor importance. Furthermore, the iiuoroscopy must last for severalminutes, whereas a radiograph is completed within a few seconds or evenin a fraction of a second.

'Ihe X-ray installation according to the invention comprises at leasttwo X-ray tubes disposed on the same side of the object to beirradiated. One of these tubes,.referred to hereinafter as the exposuretube, serves only for taking radiographs and may be stationary, whereasthe second tube, referred to hereinafter as the nuoroscopic tube servesonly for fluoroscopy and is movably arranged at a shorter distance fromthe place to be occupied by the object than is the exposure tube. Y

The installation according to the invention operates in the followingmanner: The fluoroscopic tube is placed in operation and the object tobe irradiated is located Within the ray-beam of this tube. By moving theiiuoroscopic tube in a plane parallel to an image screen, that portionof the object of which a more detailed X-ray photograph is to be takencan be readily located. The radiograph is then made by means of theexposure tube, which is arranged at a greater distance from the objectthan is the uoroscopic tube.

If the exposure tube has a iixed position so that its ray-cone strikesthe image screen within a constant framing,` it is generally desirable.to move the object until the parts to be irradiated are in the properposition relative to the framing.

For this purpose the object, together'with the iiuoroscopic tubeconnected in circuit, are moved until the radioscopic image of theportion to be radiographed falls within the area accessible to the X-raybeam of the exposing tube. To make the use of an extremely large imagescreen unnecessary, the screen maybe mechanically interconnected Withthe iiuoroscopic tube so as to follow the movements thereof.

To permit the object to be readily moved into its correct positionrelative to the X-ray beam, we provide a carrying device which can bemoved, if desired by mechanical means. In subjecting persons toirradiation a hydraulic lifting device may be used, whereby the personcan be lifted without any exertion to any desired height and with anaccurate vertical adjustment. AS a'rllle. the horizontal adjustment isnot diicult, although a mechanical device may also be used for thispurpose.

As the oroscopic tube is disposed near' the object, it does not need tobe dimensioned Afor such a great energy asis the exposure tube. Forinstantaneous exposures, it is very advantageous to use an exposure tubehaving an anode which rotates during operation, Whereas it is preferablethat the fluoroscopic tube, which requires less energy but for a longertime, be a tube of lower power having an anode provided with a coolingdevice. 4

For the convenient handling of the installation, it is in some casespreferable to providev switches associated with either the main circuitor with the auxiliary circuit of the exposure tube. These switches areso interconnected with the device for operating the iiuoroscopic tubethat they are lprevented from occupying or being moved into theirposition necessary for placing the exposure tube into operation, unlessthe fluoroscopic tube is located in its off-position.' By olf-positionof the iluoroscopic tube is meant the position occupied by this tubewhile the exposure is being` made and which position is outside of theraycone of the exposure tube.

By arranging the above-mentioned switch or system of switches so thatthey are moved by an operating device of the fluoroscopic tube into thatposition in which the lexposure tube becomes operative, the exposure isautomatically made when the uoroscopic tube is being moved into itsoff-position after the uoroscopy has taken place. On the other hand, ifmovement of the fluoroscopic tube into its off-position merely permitsthe energization of the exposure tube without actually effecting same, asafety device is obtainedwhichV prevents the exposure tube from beingprematurely placed inA circuit, Vand conse- I Vquently prevents a faultyexposure.

Such a switch may, for example, controlthef filament heating circuit ofthe cathode of the exposure tube. InV addition,-or in lieu thereof,

the switch may be associated with the circuit which-causes rotation ofthe anode ofthe exposure tube-if the tube is of the rotaryanqde type-ora second switch controlled by the position Vof theV uoroscopic tubejmaybe provided for`V I Y establishing the last-mentioned circuit.

' Y' sufliciently high voltage. A Y Y the high-tension transformersupplying charging current to the condenser may also supply the opmay beincluded in the charging circuit of the condenser. However, as thecharging current de- Vcreases as the voltage of the condenser increasesOur invention is very importar-itin connection with X-ray installationsin whichV the lenergy for making the radiographs'is obtained from acondenser Vwhich has been previously charged to a In such installations,

eratingcurrent for the iluoroscopic tube which duringY the charging, andthusthe fluoroscopic tube `Wouldbeab1e Eto `emit rays for only a limitedtime, 'Wepreferto provide a switchif ldesired with 'a1-limitingresistance `connected-in series Ytherevvfith4to shunt the condenser.This shunt vl so YLes ' ing,V in which:

circuit is Y,opened when the condenser is to be Vcharged 'and theinstallation may, if'desired, be

soY arranged that `the opening of this circuit is also effected byfo'rmade possible through, the

l displacementV of Vthe uoroscopicxtube into its off-position.` D

It isV also possible to provide a 'device by which the supply ,voltagefor the condenser charging .circuit iscut out when the circuit for theexposure Y tube 'is established; In the Yoperation of such 'a device Vitvis possible lto make 'the exposure :after Vthe, charging of thecondenser has been initiated by'inovingY the Vfluorosco'pic `tubeinto`its 'off-positio'n. However, if the switch shunting the `con-Adenser is maintained-in its/open position -by 4an kauxiliarycurrentg-'it'should not be closed by the de'encrgization .ofthis circuitwhile thel supply `v'oltag'eof the charging circuit -is being cut off,`as

in this case a Vdischargewould occur through said Vlswitch. Thereforethe shunt lswitch may be operrelay, as otherwise the two circuits wouldbe `1nterrupted simultaneously. In addition, a sai'etyswitch may beprovided topreven'tthe Vsupply"transformer from being cut VVout ofcircuit and thus to prevent theV exposure tub from .being placed incircuit unless the 'fluo- 'roscopi'c tube yoccupies its off-position.

VIn order thatour invention maybe more' clearly understood, and readilycarried into effect, We

'shall describesame more fully, byuway ofV example, with reference tothe ac companying drawsljigure lis a side elevation Vof an X-rayinstallation according to our invention, uand shows .the arrangement ofthe various parts.;

cone of the tube I. Y

`these two transformers being insulated from each Figure 2 is aschematic circuit diagram of the installation shown in Figure 1.

The X-ray installation shown in Figure 1 com- .prises an exposure X-raytube I and a fluoroscopic X-ray tube 3. The exposure tube I `is iixedlymounted upon a frame work 2 and comprises a'rotata'ble anode; whereasthe fluoroscopic tube 3 is carried by an operating mechanisrn 4comprising a U-shaped rod having on one -Vnd a handle 5 accessible tothe operator. This V1 --mechanism permits the tube 3 to be moved bothhorizontally and vertically in a plane parallel to Y a projectionscreen 1. Y

I A'personto be subjected to irradiation may, stand upon a supportingplate 6 and is thus lol cated between the tube 3 .and the screen 1. The?focal --distance of theftube .3 from the screen 'IV is, for example, 175centimeters, whereas that of the exposure tube is, for example, 2meters. It is, of course, obvious that these Vdistances may be 2 variedVinaccordancev with the characteristics of If the tube 3 is placedinoperation thereis. -pron duced upon thescreen 'l a radioscopy, which'can be'observed by an operator standing in frontof 2 thescreen at thelef-thand side of the installation. Y The supporting plate 6.canbefraisedor lowered rbylrneans of a suitable hydraulic device 8controlled by'an yelectric. motor 9. the portions of the person to Ibeirradiated afterbeing 3 Y located can be brought, under continuousobservation of the radioscopy, into such a position re1- ative to thelocation -of Va photographicrflm that *Y the portionto be irradiated'lies Within the ray- ArrangedY at the left side of the .apparatusrisY acontrol and instrument desk I0; Y 'l Y The fluoroscopic' tube 3 issupplied with operating current Yfrom a high-tension transformerY IIhaving a high-voltage winding connected throug a Yrectifying tube I2`to-the tube 3.

'Ihe cathode of `rectifier tube I2is heated from an auxiliary heatingtransformer I3, whereas the cathode of X-ray Vtube 3`is heated from anauxiliary heating transformer I4; the windings 'of other against'hightension.

The transformer II, rectifier tubellfand the u iluoroscopic tubeform,togetherA with a` high-tension condenser I5, a closed `circuit which`the charging circuit of the condenser I5.l Y

In the rear of the installation are located 'the parts of the dischargecircuit of the condenser] 5. 'I'his circuit goes from one pole I6 ofcondenser I5 through an electrically-operated switch I1, Va choke coilI8, and the X-ray tube I to the metal frame 2 which Vis Vgrounded duringthe operation Yof the apparatus and to which are also connected theother poles of rcondenser I5 and of transformer II. lAn auxiliarytransformer I9, which need not be insulatedV against high tension,serves to heat the incandescent cathode of tube I.

- In addition a .shuntconsisting of Aa -resistance 2D Yand anelectrically-operated switch 2| is con- Y nected across the condenser I5, and a transformer 6 v22 serves to supply current for rotating theanode of tube I.

The various low-tension circuits are not shown in Figure 1, vbut will bedescribed in connection Y with thecircuit diagramof Figure 2-in whichthe 7 various members are indicated by the same reference numerals asinFigure 1. l

As shown inFigure 2, the primary winding 40 of supply transformer IIislconnected through the contacts .of anelectrically-actuated double- 15pole switch 3|, and of a main switch 25 to a suitablealternating-current supply, for instance the ordinary 220 volt mains.

The coil 4| of switch 3| has one end connected to one pole of switch 25and its other end connected through a hand switch 30 to the other poleof switch 25. The contacts of relay 2| are normally closed, and uponclosure of switch 25, a current can ow from one end of secondary Winding43 of transformer I through rectifying tube I2, iiuoroscopic tube 3,resistance 20, relay 2|, and a resistance 24, back to the other end ofsecondary winding 43.

. The resistance 20 is given such a value that the voltage drop producedacross same by the passage therethrough of a current of the magnituderequired to operate tube 3 as a radioscopic tube is insignicantly smallcompared to the total voltage. If, for example, a current of 20milliamperes is used for fluorosc'opy, the resistance 20 may have avalue of 105 ohms. Thus, the voltage drop across the resistance is 2000volts which, at a total voltage of say 60 kilovolts, is relativelysmall. The resistance 2U serves to prevent, in case of a faultyconnection, the passage of an excessive current through the relay switch2|, when the condenser I5 discharges'.

The primary windings of filament supply transformers I3 and I4 areconnected in parallel with one end connected through conductor 44directly to one pole of switch 25 and with the other end connectedthrough one pole of switch 3| to the vother pole of switch 25. Thustransformers I3 and I4 are energized simultaneously with transformer I Iby closure of the switch 25 and the corresponding closure of switch 3|,whereby the installationis ready for uoroscopy. Ifafter the Yfluoroscopyhas taken place, it is desired to charge the 'condenser I5 and thenproceed with the exposure, the tube 3 is moved by means of the mech-'anism 4 (see Fig. 1) out of the radiation range of Vand back to theother pole of the supply.

Upon energization of its coil, relay 2'I closes its contacts and acurrent flows from one pole of the supply, across the contacts of`switch 2'I, through the primary windings of transformers I9 and 22 andback through conductor 44 to the other side of the supply. Consequently,the anode of exposing tube I starts rotating and the heating of Ythecathode of this tube is initiated.

The secondary winding of transformer I9, in

'addition to supplying heating current to the cathode of tube I, alsosupplies energizing current to the coil of relay 2|, which is anormally-closed relay, i. e., the contacts are open when the coil isenergized. With contacts 2| open, condens-er I5 is no longershort-circuited by resistance 20 andv becomes charged up to a voltagewhich is substantially equal to the maximum value of the voltagesupplied from transformer II.

Connected in parallel with the resistance 24 is a glow discharge tube 28which serves to indicate when the condenser has vbeen charged to theproper amount. As the voltage of the condenser increases, the chargingcurrent flowing through resistance 24 decreases to such a value that thevoltage drop across the resistance -24 is no longer suiiicient to keepthe tube 28 illuminated. Thus the extinguishment of this tube indicates.that the condenser is sufficiently charged and the exposure can takeplace. A condenser 29 shunts tube 28 and serves to insure that thedisplacement current constantly owing in the circuit does not produce inresistance 24 a voltage drop of sufficient value to cause ignition oftube 28.

When it is desired to proceed with the exposure, the switch 3i] isopened. The switch 30 previously established a circuit passing throughthe coil 4| of switch 3| through the contacts of which owed the currentfor transformers I I, I3 and I4. Upon deenergization of coil 4I,energization of the charging circuit from the network ceases. As thecoil of relay I'I is connected in series with the incandescible cathodeof tube 3, deenergization of transformer I4 due to the opening of switch30, will also deenergize relay I'I whereby its contacts will close andallow the discharge current to ow from the condenser I5 through thecontacts of relay Il, inductance I8, X-ray tube I, and back to thecondenser I5. Thus a high-energy radiation of X-rays adapted to produceanexposure of short duration on thephotographically-sensitive plate isobtained during a short time depend-,-V ing upon electric values of thecondenser discharge circuit.

To prevent relay 2| and the incandescible cathode of tube I from beingdeenergized immediately upon the opening of switch 30, the relay-2`| isprovided with a time delayof suchduration that it breaks its contactsonly after the condenser has been allowed to discharge through the tube-I As a rule, a time delay of a few tenths of a second will suffice.When, after the time delay, relay 2'I has reoccupied its olf-position asshown, the entire installation is currentless and is ready for a secondexposure by closing switch 30. IfV this is done without moving thefluoroscopic tube 3 from its off-position, thus without moving switch 25from its left-hand position, the condenser .I5 obtains without delay anew charge. Should, with the condenser so charged, tube 3 be erroneouslymoved out of its olf-position, the switch 26 would bridge its right-handcontacts, coil of switch 2| would become deenergized, and condenser I5would discharge through switch 2|. However as the limiting resistance 20is present in the discharge circuit, the discharge will not proceed toovehemently so that in this respect the'installation is protected fromdamage resulting from such faulty manipulation. A A

The right-hand contacts of the switch 26, which are closed when the tube3 is in the center of the eld of radiation, also serve as a safetymeans. If the tube 3 were moved out of yits off-position after thecondenser I 5 had been charged, it would be possible, by openingauxiliary switch 3i), to -deenergize and open switch 3| before relay 2|becornes deenergized; relayV 2| being controlledY by the delay switch2'I which remains closed fora time interval after the switch 3| hasopened. In this case the discharge of the condenser I5 would produce anundesired current flow through .the X-ray tube However, as theright-hand contacts of switch 26 are connected across switch 30 theinstallation is kept under tension even when the switch 35 is opened.

The installation is grounded at a pointf at which transformer I I,condenser I5, relay 2|, and the incandescible cathode of the X-ray tubeI are interconnected.` For this reason, asis apparent Y 7against-highvoltage, whereas the transformer I9 fromFigurel, the transformer H andthe condenser musthaveonly one pole insulated does not `have to beinsulated `at all against high voltages;VV A measuring'device 32 can .beincluded Ain the lead at this point, which device, as well as Ythe'small indicator lampY 28, does not have to be insulatedfor highvoltage against the grounded frame workgan'd can be simply mounted onthe.

control desk 10.

For limitingvthe ray coneof the tube 3, movable diaphragms operated fromthe operators position by means ofBowden wires and small regulatingknobs-on the handle 5 may be arranged in the directing cone of the saidtube.

While we have described our invention in connection vwith specificexamples and applications, we do not wish to be limited thereto butdesire Vtheappended claims to be construed as broadly .as permissibleinview of the prior art.

What we claimisz- Y 1. An YX-ray installation comprising a" station-Vary lX-ray Vtube having an anode and a cathode adapted to be heated toincandescence, means comprising a source of current 'for' energizingvsaid cathode and a switch to' interrupt the heat- 'ing current to saidcathode, a movably arranged *XV-ray tube Yfor. iiuoroscopicexamination,` said `movable tube whenin operative position beingVlocatedrfin the pathof the X-rays of said first tube, means to shiftVsaid movable tube into an off position, said switch being inoperativerelaf tion with said shifting means whereby said switch isopened'when the movable tube is shifted from Vits offposi'tion into itsoperative position, and

vmeans for impressing an 'electromotive force lacross eitherof saidX-ray tubes.V

2. YAn X-ray installation comprising an VX-ray l'tube adaptedY formaking radiograph exposures,

' and a second X-ray tube adapted for fluoroscopic examination, acondenser adapted ,to be charged lto a high tension, a'transformerhaving a 'high- -tension secondary winding, a circuit including VsaidVsecondary winding, the second tube and said condenser, a shunt circuitacrossrsaid condenser which Awhen closed permits the supply of theoperating voltage for said second tube for fluoroscopic examination,Vmeans to interrupt Vsaid shun-t connection so as to permita gradualcharging of said condenser to a voltage approximating the maximumvoltage induced inV said -high tension windinguand means forinterruptingv the.

Ycircuit for the cathode of therexposure tube and Y aY heating circuitfor the cathode of the screen-V ing tube, a resistance and arelay-operated switch Vin-series with said resistance,rthe tworbeingconnected in multiple to said capacitor, a second relay-operated switchin series with the exposure 'tube-the two being connected across saidcapacitor, the relay of the first switch being energized from theheating circuit of the cathode of the exposure tube .and the switchbeing'opened Vby the current'fiow in this circuit, and 'the relay of'the second switch being energized from the heating circuit of thescreening .tube cathode, and this second switch being opened bycurrntflowing in this circuit to preventthe discharge'of the capacitor throughthe exposure tube, and means to automatically interrupt the heatingcircuit ofthe exposure Vtube cathode and to close the rstV relay switcha short time interval after the heating of the screening tube cathode-isinterrupted.

4. 'An X-ray installation comprising an X-ray tube adapted for makingshort-time radiograph Y exposures Vand an X-'ray tube adapted forscreening work, a high-voltagey transformer having V'a primary-and asecondary winding, a condenser adapted to be charged up to a highvoltage by said transformer, a coil-operated switch and vraA ianualswitch, a primary circuit for said highvoltage transformer includingsaid coil-operated switch, an energizing circuit. for said'coilcomprising said manual switch, said energizing ycircuit beingindependent of e Ysaid coil-operated switch, said exposure tube andYscreening tube each having an incandescible cathode, separate` heatingtransformers for energizingV the cathodes of said tubes, a circuitincluding said screening tube, said secondary winding'and saidcondenser,

a shunt across said condenser having ohmic resistance and comprising arelay operated switch,

said relay being energized from the heating `transformerV of theexposure tube Yand said' 'switch being Vopen when its relay isenergized, a second V,relay'operated switch'in series with the exposureVtube and forming with said tube a shunt circuit across said condenser,the relay of saidY second switch being energizedrfrom the heatingtransformer of the screening tube and opening itsV switch whenenergized, theV screening tube being Amovable and means for shifting itfrom its operating position to an olf-position, a switching'device andmeans interconnecting same with lthe said means for shifting theVscreening tube Vso as to be operated by the latter means, saidswitching device short-circuiting the manual t Yswitch when theYscreening tube is in its operating position and closing anauxiliarycurrent circuit when the screening tube is in its off-position,a coil-actuated time-delay switch, the coil -of Vthe delay switch AbeingYenergized by said auxiliary circuit, and the time-delay switchcontrolling the heating transformer of theexposure tube, Vener-`gization of this heating transformer being` independent of thecoil-operated switch, kthe heating transformer for the vscreening tubecathode being controlled by said coil-operated switch. Y

5. An X-ray installation comprising a framework having a front wall, arear Wall, and a winldow in the front wall, a supporting plate for thepatient to be radiated disposed before said front Wall, a supportdisposed infront offsaid plate adapted to carry a fluorescent screen anda pho- -tographic cassette, a control panelY on Ysaid support, an X-raytube Vadapted for uoroscopic work in said framework, said tube beingmovably disposed at a .short distance in the rearof said 'front wall,Vmeans comprising 'a handleY bar disposed in the vicinity of saidcontrol ,panel and Vadapted for moving said X-ray tube in a 'planeparallel to the front wal1,'a secondX-,ray tube adapted for takingradiographs, Vsaid second tube being fixedly mounted close to the rearwall of the framework and directing its rays through said window'of thefront wall, and a high-tension current source and connecting meansyibetween said source and said tubes, said high-tension source andconnecting means being enclosed within said framework.

6. An X-ray installation comprising a stationary X-ray tube adapted fortaking exposures of short duration, and a movable X-ray tube adapted forcontinuous screening work, an operative circuit for each of said tubes,said screening tube, in its operating position assuming an intermediateposition between the exposure tube and the place to be irradiated, thusin the path of the X-rays of the exposure tube, means to shift thescreening tube into an oir-position and out of said path, means forswitching on the current in the operative circuit of the exposure tubeto place said exposure tube into operation, said latter means being inoperative relation to said shifting means and so controlled thereby asto prevent the exposure tube from being placed into operation unless thescreening tube occupies its off-position.

7. An X-ray installation comprising a stationary X-ray tube for makingradiographs, a movable X-ray tube for iluoroscopic examination, saidsecond tube, when in its operative position, being located in the pathof the X-rays of said rst tube and being movable into an oif positionoutside of the path of said rays, a high-tension circuit including saidrst tube, a source of high-tension and a circuit-closer, a secondhightension circuit including a second source of hightension and saidsecond tube, said circuit-closer being interconnected with said movabletube whereby the closure of said circuit-closer is prevented unless thesecond tube is in its off-position, and said circuit-closer is openedwhen the second tube is removed from its off-position.

8. An X-ray installation comprising a stationary X-ray tube having anincandescent cathode and adapted for making radiographic exposures, amovable X-ray tube adapted for screening work, a high-tensiontransformer, a capacitor adapted to be charged to high tension by saidtransformer, a high-tension circuit including said rst tube and saidcapacitor, a second high-tension circuit including said second tube andtransformer, a third circuit including a source of current forenergizing said cathode, a resistance and a coilactuated switch inseries connection across said capacitor, means to shift said second tubeinto an off-position outside of the X-ray beam of the rst tube, saidsource being adapted to energize said coil to open said switch, a secondswitch disposed in said third circuit, means under the action of saidshifting means to close said second switch when the second tube is inits oir-position, said capacitor being gradually charged to a voltageapproximating the maximum voltage of said transformer, and means tocause said capacitor to discharge through said exposure tube for a timeinterval which is short with respect to its charging time.

9. An X-ray installation comprising a stationary X-ray tube for takingradiographs and having a movable anticathode, said tube being providedwith an electromagnetic stator for imparting rotative motion to saidanticathode, a movably-arranged X-ray tube for luoroscopic examination,high-tension operative circuits for Y said X-ray tubes includinghigh-tension switches to switch on the operative currents of said X-raytubes, means for shifting said movable tube into an off-position outsidethe path of the rays of the first tube, a circuit for said statorcomprising an electrically-operated circuit-closer, and an operatingcircuit for said circuit-closer including means for initiating andterminating the current fiow therein, said latter means being inoperative relation with said means for shiftin the movable tube, wherebysaid circuit closer is closed when the movable tube is in itsolf-position.v

10. An X-ray inst-allation comprising an X- ray tube for makingphotographic exposures, a second X-ray tube for fluoroscopicexamination, said first tube having a considerably higher load capacitythan said second tube, said second tube being adapted to be continuouslyloaded with a power su'icient for its intended purpose, and means forsupplying high tension to said tubes, said means comprising ahigh-tension condenser and a high-tension transformer, said transformersupplying both the charging energy for said condenser and the energy forsaid second tube, said condenser, after being charged up by sai-dtransformer to the working voltage of the rst tube, supplying to thistube in a single-beat discharge the energy required for one exposure.

11. An apparatus for making radiographs of objects, comprising astationary X-ray receiving means, a stationary radiographic X-ray tubefixed with respect to said means with its raypath directed to energizesaid means, a fluoroscopic X-ray tube movably mounted between said meansand said radiographic X-ray tube and movable into position with its raypath directed to energize said means and to a position ofnon-interference with the ray path of said radiographic tube, and anadjustable support for the object to be radiographed locatedintermediate said means and said iiuoroscopic X-ray tube; said support,iiuoroscopic tube, and X-ray receiving means being capable of relativeadjustment to position the object by fluoroscopic examination in theray-path of said radiographic tube.

12. An apparatus for making radiographs of a desired portion of anobject comprising a stationary X-ray receiving means, a stationaryradiographic X-ray tube xed with respect to said means with its ray-pathdirected to energize said means, and means comprising a fluoroscopicX-ray tube movably mounted between said X- ray receiving means and saidradiographic tube to position said fluoroscopic tube within the raypathof said radiographic tube, said uoroscopic tube being movable into anoff-position of non-interference with the ray-beam of said radiographictube and being movable in accordance with the placement of said objectin positions intermediate the X-ray receiving means and fluoroscopictube and into a position in which the desired portion of the object lieswithin the ray-path of the radiographic tube.

ALFRED KUNTKE. WILLEM HONDIUS ZBOLDINGH.

